Air conditioning reheat systems and methods thereto

ABSTRACT

The disclosed technology includes systems and methods for controlling an air conditioning system. The method of controlling the air conditioning system can include receiving air temperature data from an air temperature sensor and determining that the air conditioning system should operate in a reheat mode based on the air temperature being less than a threshold air temperature. The method can include outputting a control signal to a first electronic expansion valve to close and thereby prevent refrigerant to flow through an outdoor condenser coil. The method can also include outputting a control signal to a second electronic expansion valve to open and thereby permit refrigerant to flow through a reheat coil.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.17/093,868, filed Nov. 10, 2020, the entirety of which is herebyincorporated by reference.

FIELD OF TECHNOLOGY

The present disclosure relates generally to systems and methods forcontrolling air conditioning systems, and, more specifically, to systemsand methods for controlling a reheat cycle of an air conditioningsystem.

BACKGROUND

Air conditioning systems are commonly used to create a comfortableclimate for occupants of a building by providing cool air to thebuilding. To maintain a comfortable climate during periods of highrelative humidity, some air conditioning systems operate to causemoisture to condense on the surface of the cool evaporator coil andremove humidity from the building, even when the air temperature in thebuilding is close to or below the set temperature for the airconditioning system. To ensure the conditioned air supplied to thebuilding is not uncomfortably cold, however, some air conditioningsystems utilize a reheat mode to re-increase the temperature of theconditioned air back to approximately the same temperature as the airalready in the building.

When operating in a reheat mode, many air conditioning systems utilize areheat coil positioned downstream of the indoor evaporator coil. Aportion of the refrigerant in the system is routed to the reheat coil,rather than the outdoor condenser coil, to raise the temperaturesupplied to the building to approximately the same temperature as theair returning to the air conditioning system. This arrangement allowsthe air conditioner to remove humidity from the building for longerperiods of time because the occupied space is not overcooled, and thecompressor load is reduced by rejecting heat to the supply airstreamwhich is typically at a lower temperature than the outdoor air.Furthermore, some systems include an indoor relative humidity sensorthat can be used to determine whether the humidity in the building isbelow a threshold humidity level.

Some air conditioning systems that include a reheat coil control thereheat cycle by installing a three-way solenoid valve upstream of thereheat coil and a thermal expansion valve downstream of the reheat coil.Three-way solenoid valves, however, are typically expensive and noisy,and the addition of a thermal expansion valve downstream of the reheatcoil can further increase the overall cost of the air conditioningsystem. Furthermore, most three-way solenoid valves are unable to bemodulated. Because most three-way solenoid valves are unable to bemodulated, air conditioning systems having a three-way solenoid valvecannot be modulated between a cooling only mode and a reheat mode,resulting in a less efficient operation of the air conditioning systemand less control of the indoor relative humidity.

What is needed, therefore, is a system and method of operating an airconditioning system that can modulate a reheat cycle and utilizes moreeconomical components. These and other problems are addressed by thetechnology disclosed herein.

SUMMARY

The disclosed technology relates generally to systems and methods forcontrolling air conditioning systems, and, more specifically, to systemsand methods for controlling a reheat cycle of an air conditioningsystem.

The disclosed technology can include a method of controlling an airconditioning system. The method can include receiving, from an airtemperature sensor, temperature data indicative of an air temperature inthe air conditioning system and determining that the air conditioningsystem should operate in a reheat mode based at least in part on the airtemperature being less than a threshold air temperature. Alternativelyor in addition, the method can include receiving, from an indoorrelative humidity sensor, humidity data indicative of an air humidity inthe air conditioning system and determining that the air conditioningsystem should operate in a reheat mode based at least in part on the airhumidity being less than a threshold air humidity. In response todetermining that the air conditioning system should operate in thereheat mode, the method can include outputting a control signal to afirst electronic expansion valve to close the first electronic expansionvalve, thereby preventing a refrigerant in the air conditioning systemfrom flowing through an outdoor condenser coil. The method can alsoinclude outputting a control signal to a second electronic expansionvalve to open the second electronic expansion valve, thereby permittingthe refrigerant to flow through a reheat coil.

In response to determining that the air conditioning system shouldoperate in the reheat mode, the method can further include outputting acontrol signal to an outdoor condenser coil fan to turn off. The methodcan also include determining that the air conditioning system shouldoperate in a cooling mode based at least in part on the air temperaturebeing greater than or equal to the threshold air temperature. Inresponse to determining that the air conditioning system should operatein a cooling mode, the method can include outputting a control signal tothe first electronic expansion valve to open the first electronicexpansion valve, thereby permitting the refrigerant in the airconditioning system to flow through the outdoor condenser coil. Themethod can also include outputting a control signal to the secondelectronic expansion valve to open the second electronic expansionvalve, thereby preventing the refrigerant from flow through the reheatcoil and outputting a control signal to an outdoor condenser coil fan toturn on.

The method can further include receiving, from a refrigerant temperaturesensor, refrigerant temperature data indicative of a refrigeranttemperature of refrigerant in the air conditioning system anddetermining that the air conditioning system should operate in amodulating reheat mode based at least in part on the air temperaturebeing less than the threshold air temperature and the refrigeranttemperature being less than a threshold refrigerant temperature. Inresponse to determining that the air conditioning system should operatein a modulating reheat mode, the method can include outputting a controlsignal to the first electronic expansion valve to modulate the firstelectronic expansion valve to control a flow of the refrigerant throughthe outdoor condenser coil, and outputting a control signal to thesecond electronic expansion valve to modulate the second electronicexpansion valve to control a flow of the refrigerant through the reheatcoil.

The temperature data can be indicative of a superheat of refrigerantflowing through an evaporator. The method can include determining thatan outdoor condenser coil fan should be operated based at least in parton the refrigerant temperature data indicating that the temperature ofthe refrigerant is less than the threshold refrigerant temperature. Inresponse to determining that the outdoor condenser coil fan should beoperated, the method can include outputting a control signal to operatethe outdoor condenser coil fan.

Operating the outdoor condenser coil fan can include determining that aspeed of the outdoor condenser coil fan should be modulated based atleast in part on a difference between the refrigerant temperature andthe threshold refrigerant temperature. In response to determining that aspeed of the outdoor condenser coil fan should be modulated, the methodcan include outputting a control signal to modulate the speed of theoutdoor condenser coil fan.

Determining that the air conditioning system should operate in amodulating reheat mode further can also include determining that thefirst electronic expansion valve should be opened a predetermined amountbased at least in part on the air temperature data indicating that theair temperature is less than the threshold air temperature and less thana second threshold air temperature. The threshold air temperature can begreater than the second threshold air temperature. The method can alsoinclude determining that the second electronic expansion valve should bemodulated based at least in part on the refrigerant temperature.

In response to determining that the first electronic expansion valveshould be opened the predetermined amount, the method can includeoutputting a control signal to the first electronic expansion valve toopen the first electronic expansion valve the predetermined amount. Inresponse to determining that the second electronic expansion valveshould be modulated, the method can include outputting a control signalto modulate the second electronic expansion valve, wherein the secondelectronic expansion valve is modulated to maintain the refrigeranttemperature based at least in part on the threshold refrigeranttemperature.

Determining that the air conditioning system should operate in amodulating reheat mode further can include determining that the secondelectronic expansion valve should be opened a predetermined amount basedat least in part on the air temperature data indicating that the airtemperature is less than the threshold air temperature and greater thana second threshold air temperature. The threshold air temperature can begreater than the second threshold air temperature. The method can alsoinclude determining that the first electronic expansion valve should bemodulated based at least in part on the refrigerant temperature

In response to determining that the second electronic expansion valveshould be opened the predetermined amount, the method can includeoutputting a control signal to the second electronic expansion valve toopen the second electronic valve the predetermined amount. In responseto determining that the first electronic expansion valve should bemodulated, the method can include outputting a control signal tomodulate the first electronic expansion valve. The first electronicexpansion valve can be modulated to maintain the refrigerant temperaturebased at least in part on the threshold refrigerant temperature.

The method can also include receiving, from a humidity sensor, humiditydata indicative of a humidity level of air in the air conditioningsystem and determining that the air conditioning system should operatein a reheat mode based at least in part on the humidity level beinggreater than a threshold humidity level.

The disclosed technology can also include a non-transitory,computer-readable medium having instructions stored thereon that, whenexecuted by one or more processors, cause a controller to receive, froman air temperature sensor, temperature data indicative of an airtemperature in an air conditioning system and determine that the airconditioning system should operate in a reheat mode based at least inpart on the air temperature being less than a threshold air temperature.The instructions can also cause the controller to output a controlsignal to a first electronic expansion valve to close the firstelectronic expansion valve, thereby preventing a refrigerant in the airconditioning system to flow through an outdoor condenser coil, andoutput a control signal to a second electronic expansion valve to openthe second electronic expansion valve, thereby permitting therefrigerant to flow through a reheat coil.

The instructions, when executed by the one or more processors, canfurther cause the controller to output a control signal to an outdoorcondenser coil fan to turn off. The instructions, when executed by theone or more processors, can also cause the controller to determine thatthe air conditioning system should operate in a cooling mode based atleast in part on the air temperature being greater than or equal to thethreshold air temperature. The instructions can also cause thecontroller to output a control signal to the first electronic expansionvalve to open the first electronic expansion valve, thereby permitting arefrigerant in the air conditioning system to flow through the outdoorcondenser coil, output a control signal to the second electronicexpansion valve to close the second electronic expansion valve, therebypreventing the refrigerant from flowing through the reheat coil, andoutput a control signal to the outdoor condenser coil fan to turn on.

The instructions can also cause the controller to receive, from arefrigerant temperature sensor, refrigerant temperature data indicativeof a refrigerant temperature of refrigerant in the air conditioningsystem. Additionally, the instructions can also cause the controller to,determine that the air conditioning system should operate in amodulating reheat mode based at least in part on the air temperaturebeing less than the threshold air temperature and the refrigeranttemperature being less than a threshold refrigerant temperature, outputa control signal to the first electronic expansion valve to modulate thefirst electronic expansion valve to control a flow of the refrigerantthrough the outdoor condenser coil, and output a control signal to thesecond electronic expansion valve to modulate the second electronicexpansion valve to control a flow of the refrigerant through the reheatcoil.

The temperature data can be indicative of an evaporator superheat. Todetermine that the air conditioning system should operate in amodulating reheat mode, the instructions, when executed by the one ormore processors, can cause the controller determine that the firstelectronic expansion valve should be opened to less than 50% capacitybased at least in part on the air temperature data indicating that theair temperature is less than the threshold air temperature and less thana second threshold air temperature, the threshold air temperature beinggreater than the second threshold air temperature. The instructions canalso cause the controller to determine that the second electronicexpansion valve should be modulated based at least in part on therefrigerant temperature, output a control signal to the first electronicexpansion valve to open the first electronic valve to less than 50%capacity, and output a control signal to modulate the second electronicexpansion valve, wherein the second electronic expansion valve ismodulated to maintain the refrigerant temperature based at least in parton the threshold refrigerant temperature.

To determine that the air conditioning system should operate in amodulating reheat mode, the instructions, when executed by the one ormore processors, can cause the controller to determine that the secondelectronic expansion valve should be opened less than 50% capacity basedat least in part on the air temperature data indicating that the airtemperature is less than the threshold air temperature and greater thana second threshold air temperature, the threshold air temperature beinggreater than the second threshold air temperature. The instructions canalso cause the controller to determine that the first electronicexpansion valve should be modulated based at least in part on therefrigerant temperature, output a control signal to the secondelectronic expansion valve to open the second electronic valve less than50% capacity, and output a control signal to modulate the firstelectronic expansion valve, wherein the first electronic expansion valveis modulated to maintain the refrigerant temperature based at least inpart on the threshold refrigerant temperature.

The instructions can also cause the controller to determine that theoutdoor condenser coil fan should be operated based at least in part onthe refrigerant temperature data indicating that the temperature of therefrigerant is less than the threshold refrigerant temperature andoutput a control signal to operate the outdoor condenser coil fan.

To output a control signal to operate the outdoor condenser coil fan,the instructions, when executed by the one or more processors, can causethe controller to determine a speed of the outdoor condenser coil fanshould be modulated based at least in part on a difference between therefrigerant temperature and the threshold refrigerant temperature andoutput a control signal to modulate the speed of the outdoor condensercoil fan.

The instructions can also cause the controller to receive, from ahumidity sensor, humidity data indicative of a humidity level of air inthe air conditioning system and determine that the air conditioningsystem should operate in a reheat mode based at least in part on thehumidity level being greater than a threshold humidity level.

Additional features, functionalities, and applications of the disclosedtechnology are discussed herein in more detail.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate multiple examples of thepresently disclosed subject matter and serve to explain the principlesof the presently disclosed subject matter. The drawings are not intendedto limit the scope of the presently disclosed subject matter in anymanner.

FIG. 1 illustrates an example air conditioning system having a reheatsystem, in accordance with the disclosed technology.

FIG. 2 is a flowchart illustrating an example method of controlling areheat cycle of an air conditioning system, in accordance with thedisclosed technology.

FIG. 3 is a flowchart illustrating an example method of controlling areheat cycle of an air conditioning system, in accordance with thedisclosed technology.

FIG. 4 is a flowchart illustrating an example method of controlling areheat cycle of an air conditioning system, in accordance with thedisclosed technology.

FIG. 5 is a flowchart illustrating an example method of controlling areheat cycle of an air conditioning system, in accordance with thedisclosed technology.

FIG. 6 is a flowchart illustrating an example method of controlling areheat cycle of an air conditioning system, in accordance with thedisclosed technology.

DETAILED DESCRIPTION

The disclosed technology relates generally to systems and methods forcontrolling a reheat cycle of an air conditioning system. The airconditioning system can include two or more electronic expansion valvescontrolled by a controller to direct an amount of refrigerant through areheat coil. The reheat coil can be positioned in an air duct downstreamof the indoor evaporator coil such that the reheat coil can add heat tothe air directed over the evaporator coil prior to the air returning tothe building. The controller can be configured to modulate one or moreelectronic expansion valves to ensure the reheat coil sufficiently heatsthe air supplied to the building. The controller can also modulate oneor more electronic expansion valves to maintain a superheat of therefrigerant in the air conditioning system. As will be appreciated byone of skill in the art, superheat of the refrigerant occurs when therefrigerant is heated above its boiling point. Accurately controllingthe superheat of the refrigerant can be critical to the operation of theair conditioning system because it protects the compressor from damagethat could occur from liquid refrigerant entering the compressor andalso ensures the system operates efficiently. Furthermore, bysimultaneously controlling the heat output of the reheat coil and thesuperheat of the air conditioning system, the controller can ensure theair conditioning system more efficiently maintains a comfortable climatewithin the building. Systems and methods of controlling a reheat cycleof an air conditioning system are more fully described herein.

Although certain examples of the disclosed technology are explained indetail herein, it is to be understood that other examples, embodiments,and implementations of the disclosed technology are contemplated.Accordingly, it is not intended that the disclosed technology is limitedin its scope to the details of construction and arrangement ofcomponents expressly set forth in the following description orillustrated in the drawings. The disclosed technology can be implementedin a variety of examples and can be practiced or carried out in variousways. In particular, the presently disclosed subject matter is describedin the context of being a system and method for controlling a reheatcycle of an air conditioning system. The present disclosure, however, isnot so limited, and can be applicable in other contexts. The presentdisclosure, for example and not limitation, can include other airconditioning or fluid conditioning systems used in industrial ormanufacturing applications. For example, the disclosed technology caninclude heat pump drying systems generally used in drying or preservingseed, grain, textiles, paper, works of art, wood, or any other spaceand/or object that would optimally be stored in a temperature andhumidity-controlled location. Such implementations and applications arecontemplated within the scope of the present disclosure. Accordingly,when the present disclosure is described in the context of being asystem and method for controlling a reheat cycle of an air conditioningsystem, it will be understood that other implementations can take theplace of those referred to.

It should also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an,” and “the” include pluralreferences unless the context clearly dictates otherwise. References toa composition containing “a” constituent is intended to include otherconstituents in addition to the one named.

Also, in describing the examples, terminology will be resorted to forthe sake of clarity. It is intended that each term contemplates itsbroadest meaning as understood by those skilled in the art and includesall technical equivalents which operate in a similar manner toaccomplish a similar purpose.

Ranges may be expressed herein as from “about” or “approximately” or“substantially” one particular value and/or to “about” or“approximately” or “substantially” another particular value. When such arange is expressed, the various examples of the disclosed technologyincludes from the one particular value and/or to the other particularvalue. Further, ranges described as being between a first value and asecond value are inclusive of the first and second values. Likewise,ranges described as being from a first value and to a second value areinclusive of the first and second values.

Herein, the use of terms such as “having,” “has,” “including,” or“includes” are open-ended and are intended to have the same meaning asterms such as “comprising” or “comprises” and not preclude the presenceof other structure, material, or acts. Similarly, though the use ofterms such as “can” or “may” are intended to be open-ended and toreflect that structure, material, or acts are not necessary, the failureto use such terms is not intended to reflect that structure, material,or acts are essential. To the extent that structure, material, or actsare presently considered to be essential, they are identified as such.

It is also to be understood that the mention of one or more method stepsdoes not preclude the presence of additional method steps or interveningmethod steps between those steps expressly identified. Moreover,although the term “step” can be used herein to connote different aspectsof methods employed, the term should not be interpreted as implying anyparticular order among or between various steps herein disclosed unlessand except when the order of individual steps is explicitly required.Further, the disclosed technology does not necessarily require all stepsincluded in the example methods and processes described herein. That is,the disclosed technology includes methods that omit one or more stepsexpressly discussed with respect to the examples provided herein.

The components described hereinafter as making up various elements ofthe disclosed technology are intended to be illustrative and notrestrictive. Many suitable components that would perform the same orsimilar functions as the components described herein are intended to beembraced within the scope of the disclosed technology. Such othercomponents not described herein can include, but are not limited to, forexample, similar components that are developed after development of thepresently disclosed subject matter.

Referring now to the drawings, in which like numerals represent likeelements, examples of the present disclosure are herein described. FIG.1 illustrates an air conditioning system 100 having a reheat system, inaccordance with the disclosed technology. The air conditioning system100 can include a condenser coil 102, an evaporator coil 126, and acompressor 106. The condenser coil 102, the evaporator coil 126, and thecompressor 106 can each be in fluid communication with each other viaone or more refrigerant lines 104 configured to direct refrigerant inthe air conditioning system 100. As will be appreciated, the airconditioning system 100 can be configured to provide cool air to abuilding by removing heat from the building via the evaporator coil 126and releasing the heat to the ambient air via the condenser coil 102through a refrigeration cycle.

The condenser coil 102 can be located outside of a building or otherwisein a location where heat contained in the refrigerant can be released toambient air (e.g., the condenser coil 102 can be located indoors withreleased heat being vented to an outdoor location). The evaporator coil126, on the other hand, can be located inside of the building orotherwise in a location where air from the inside of the building can bedirected across the evaporator coil 126 and heat can be removed from theair. In other words, the condenser coil 102 and the evaporator coil 126can be separated by a bulkhead 114 or other partition such that thetemperature of the air proximate the condenser coil 102 can be differentfrom the ambient air proximate the evaporator coil 126.

The condenser coil 102 and the evaporator coil 126 can be any kind ofheat exchanger coil configured to facilitate heat transfer between arefrigerant and an ambient fluid. Furthermore, the condenser coil 102and the evaporator coil 126 can be made from any type of material thatcan effectively exchange heat, including copper, aluminum, stainlesssteel, gold, silver, gallium, indium, thallium, graphite, compositematerials, or any other material that is appropriate for the givenapplication.

To help facilitate heat transfer at the condenser coil 102, the airconditioning system 100 can include a condenser coil fan 110, or similarair moving device, configured to direct ambient air across the condensercoil 102. The condenser coil fan 110 can be configured to simply beturned on and off as necessary, or the condenser coil fan 110 can beconfigured such that a speed of the condenser coil fan 110 can bemodulated between various speeds. As will be described in greater detailherein, the condenser coil fan 110 can be configured to cause more heattransfer at the condenser coil 102 as necessary to control a superheatof the air conditioning system. For example, in air conditioning systems100 that include a condenser coil fan 110 capable of being modulated,the speed of the condenser coil fan 110 can be modulated to help controlheat release at the condenser coil 102 and consequently maintainsuperheating of the air conditioning system 100.

The compressor 106 can be configured to circulate a refrigerant in theair conditioning system 100 to facilitate heat exchange at the condensercoil 102 and the evaporator coil 126. The compressor 106 can be any typeof compressor used in air conditioning systems. For example, thecompressor 106 can be a positive displacement compressor, areciprocating compressor, a rotary screw compressor, a rotary vanecompressor, a rolling piston compressor, a scroll compressor, adiaphragm compressor, a dynamic compressor, an axial compressor, or anyother type of compressor suitable for the particular application.

The air conditioning system 100 can include a reheat cycle refrigerantline 108 in fluid communication with the refrigerant line 104. Thereheat cycle refrigerant line 108 can be configured to direct therefrigerant, from a point downstream of the compressor 106 and upstreamof the condenser coil 102, through a reheat coil 120, and back to therefrigerant line 104 upstream of the evaporator coil 126. In this way,the reheat cycle refrigerant line 108 can be configured to direct eitherall or part of the refrigerant vapor through the reheat coil 120 ratherthan through the condenser coil 102. As will be appreciated, bydirecting some refrigerant through the reheat coil 120 rather thanthrough the condenser coil 102, the redirected, heated refrigerant vaporcan release heat to the indoor ambient air (e.g. indoor air) proximatethe reheat coil 120 to raise the temperature of the ambient air.Furthermore, by positioning the reheat coil 120 downstream of the airflowing over the evaporator coil 126, the cool, dehumidified airdirected from the evaporator coil 126 can be heated prior to beingdelivered to the building. In this way, the air conditioning system 100can be configured such that the evaporator coil 126 can be at a lowertemperature to cause moisture in the air to condense at the evaporatorcoil 126 and moisture can be removed from the air creating a moreenjoyable climate for occupants of the building. Furthermore, the reheatcoil 120 can help to ensure the air supplied by the air conditioningsystem to the building is not uncomfortably cold. Stated otherwise, theevaporator coil 126 can transition passing ambient air into cool,dehumidified air, and the reheat coil 120 can transition the cool,dehumidified air into re-heated (e.g., to room temperature, to a targettemperature, etc.), dehumidified air.

To help control the temperature of the air supplied by the airconditioning system 100, the air conditioning system 100 can have one ormore temperature sensors 116 (shown in FIG. 1 as two sensors temperaturesensors 116A and 116B) configured to detect a temperature of air in thesystem 100. For example, a temperature sensor 116A can be installed inan air flow path proximate to, or downstream of, the reheat coil 120 andcan be configured to detect a temperature of the air downstream of thereheat coil 120. Alternatively or in addition, a temperature sensor 116Bcan be installed in an air flow path proximate to, or upstream of, theevaporator coil 126 and be configured to detect a temperature of the airupstream of the evaporator coil 120. The temperature sensors 116 caneach be configured to output temperature data and be in communicationwith a controller 130. As will be described in greater detail herein,the temperature data provided by the temperature sensors 116 can be usedby the controller 130 to determine actions based on current systemconditions. For example, the temperature data from temperature sensors116 can be used by the controller to determine how to operate the reheatcoil 120 such that air supplied from the air conditioning system 100 ismaintained within an acceptable temperature range.

Although two temperature sensors 116 are depicted in FIG. 1 , the system100 can include one, two, three, four, five, or more temperature sensors116, and the number of temperature sensors used can be selecteddepending on the application or any number of reasons. For example, thesystem 100 can include only temperature sensor 116A to measure thetemperature of the air downstream of the reheat coil 120, or the system100 can include only temperature sensor 116B to measure the temperatureof the air upstream of the evaporator coil 126. Alternatively, thesystem 100 can include three, four, five, or more temperature sensors116 installed in various locations throughout the air conditioningsystem 100. For example, additional temperature sensors can be installedproximate the condenser coil 102, downstream of the evaporator coil 126,in various locations throughout the building, or even outside of thebuilding. As will be appreciated, the number of temperature sensors andthe location of the temperature sensors can be varied depending on theparticular application.

The air conditioning system 100 can include a refrigerant temperaturesensor 128 configured to detect a temperature of the refrigerant in thesystem 100. For example, and as depicted in FIG. 1 , the refrigeranttemperature sensor 128 can be located in a refrigerant path downstreamof the evaporator coil 126 and be configured to detect a temperature ofthe refrigerant at that location. The air conditioning system 100 caninclude refrigerant temperature sensors 128 installed in variouslocations throughout the air conditioning system 100. For example, theair conditioning system 100 can include a refrigerant temperature sensor128 located upstream of the evaporator coil 126, downstream of thecompressor 106, downstream of the condenser coil 102, downstream of thereheat coil 120, and/or other locations as suitable for the particularapplication. As will be appreciated, the refrigerant temperature sensor128 can be configured to output temperature data to the controller 130.

The temperature sensor(s) 116 and/or refrigerant temperature sensor 128can each be any type of temperature sensor capable of measuring atemperature and providing temperature data indicative of the measuredtemperature to the controller 130. For example, the temperature sensors116 and refrigerant temperature sensor 128 can each be thermocouples,resistor temperature detectors, thermistors, infrared sensors,semiconductors, or any other type of sensors as would be appropriate fora given use or application. All temperature sensors of the system 100can be the same type of temperature sensor, or the system 100 caninclude different types of temperature sensors. For example, temperaturesensor 116A can be a thermistor, while temperature sensor 128 can be athermocouple. One skilled in the art will appreciate that the type,location, and number of temperature sensors can vary depending on theapplication.

The air conditioning system 100 can include one or more humidity sensors117 (shown in FIG. 1 as two humidity sensors 117A and 117B). Thehumidity sensors 117 can be configured to detect a humidity level (i.e.,a moisture content) of ambient air. For example, humidity sensor 118Acan be configured to detect a moisture content of the ambient airreturning from the building, and humidity sensor 117A can be configuredto detect a moisture content of the air being supplied to the building.As will be appreciated, the humidity sensors 117 can be any type ofhumidity sensor capable of detecting a moisture content of air andsupplying the humidity data to the controller 130. For example, thehumidity sensors 117 can each be a hygrometer, a capacitive humiditysensor, a resistive humidity sensor, a thermal conductivity humiditysensor, or any other suitable type of humidity sensor for theapplication. All humidity sensors of the system 100 can be the same typeof humidity sensor, or the system 100 can include different types ofhumidity sensors. For example, humidity sensor 117A can be a thermalconductivity humidity sensor, while humidity sensor 117B can be aresistive humidity sensor. One skilled in the art will appreciate thatthe type, location, and number of humidity sensors 117 can varydepending on the application.

The air conditioning system 100 can further include a pressure sensor129 configured to detect a pressure of the refrigerant in the airconditioning system 100. The pressure sensor 129 can be any type ofpressure sensor capable of detecting a pressure in the system 100. Forexample, the pressure sensor 129 can be a capacitive sensor, aninductive pressure sensor, a potentiometric pressure sensor, apiezoelectric sensor, an optical sensor, a Micro Electro-Mechanical(MEMS) sensor, a variable reluctance pressure sensors, a strain gaugepressure sensor, or any other type of pressure sensor capable ofmeasuring a pressure of the refrigerant in the system 100. Furthermore,although only a single pressure sensor 129 is shown in FIG. 1 , it willbe appreciated that more than one pressure sensor 129 can be included inthe system 100. For example, one or more pressure sensors 129 can beinstalled upstream of the evaporator coil 126, downstream of thecompressor, downstream of the condenser coil 102, downstream of thereheat coil 120, and/or upstream or downstream of the electronicexpansion valves (EEV1 and EEV2). Furthermore, the pressure sensor 129can be configured to output pressure data to the controller 130 to helpcontrol the air conditioning system 100. If multiple pressure sensors129 are included, all pressure sensors 129 of the system 100 can be thesame type of pressure sensor, or the system 100 can include differenttypes of pressure sensors. For example, a first pressure sensor 129 canbe a piezoelectric sensor, while a second pressure sensor 129 can be aninductive pressure sensor. One skilled in the art will appreciate thatthe type, location, and number of pressure sensors 129 can varydepending on the application.

The air conditioning system 100 can have at least two electronicexpansion valves (EEVs) configured to control a flow of the refrigerantthrough the system 100. A first electronic expansion valve EEV1 can beinstalled downstream of the condenser coil 102 and upstream of theevaporator coil 126. A second electronic expansion valve EEV2 can beinstalled downstream of the reheat coil 120 and upstream of theevaporator coil 126. The EEVs can be any type of electronic expansionvalve capable of being controlled by the controller 130. For example,the EEVs can be a solenoid (or pulse) electric valve, an analog electricvalve, a heat motor valve, or a stepper motor valve or a valve thatincludes other electromechanical components that can cause the EEVs toopen, close, and/or modulate between an open and a closed position. Aswill be appreciated, the EEVs can be configured to receive a controlsignal from a controller 130 and change a position of the valve based onthe received control signal.

The controller 130 can have a memory 132, a processor 134, and acommunication interface 136. The controller 130 can be a computingdevice configured to receive data, determine actions based on thereceived data, and output a control signal instructing one or morecomponents of the system 100 to perform one or more actions. One ofskill in the art will appreciate that the controller 130 can beinstalled in any location, provided the controller 130 is incommunication with at least some of the components of the system 100.Furthermore, the controller 130 can be configured to send and receivewireless or wired signals and the signals can be analog or digitalsignals. The wireless signals can include Bluetooth™, BLE, WiFi™,ZigBee™, infrared, microwave radio, or any other type of wirelesscommunication as may be suitable for the particular application. Thehard-wired signal can include any directly wired connection between thecontroller and the other components. For example, the controller 130 canhave a hard-wired 24 VDC connection to EEV1 and EEV2. Alternatively, thecomponents can be powered directly from a power source and receivecontrol instructions from the controller 130 via a digital connection.The digital connection can include a connection such as an Ethernet or aserial connection and can utilize any suitable communication protocolfor the application such as Modbus, fieldbus, PROFIBUS, SafetyBus p,Ethernet/IP, or any other suitable communication protocol for theapplication. Furthermore, the controller 130 can utilize a combinationof wireless, hard-wired, and analog or digital communication signals tocommunicate with and control the various components. One of skill in theart will appreciate that the above configurations are given merely asnon-limiting examples and the actual configuration can vary depending onthe particular application.

The controller 130 can include a memory 132 that can store a programand/or instructions associated with the functions and methods describedherein and can include one or more processors 134 configured to executethe program and/or instructions. The memory 132 can include one or moresuitable types of memory (e.g., volatile or non-volatile memory, randomaccess memory (RAM), read only memory (ROM), programmable read-onlymemory (PROM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), magneticdisks, optical disks, floppy disks, hard disks, removable cartridges,flash memory, a redundant array of independent disks (RAID), and thelike) for storing files including the operating system, applicationprograms (including, for example, a web browser application, a widget orgadget engine, and or other applications, as necessary), executableinstructions and data. One, some, or all of the processing techniques ormethods described herein can be implemented as a combination ofexecutable instructions and data within the memory.

The controller 130 can also have a communication interface 136 forsending and receiving communication signals between the variouscomponents. Communication interface 136 can include hardware, firmware,and/or software that allows the processor(s) 134 to communicate with theother components via wired or wireless networks, whether local or widearea, private or public, as known in the art. Communication interface136 can also provide access to a cellular network, the Internet, a localarea network, or another wide-area network as suitable for theparticular application.

Additionally, the controller 130 can have or be in communication with auser interface 138 for displaying system information and receivinginputs from a user. The user interface 138 can be installed locally onthe system 100 or be a remotely controlled device such as a mobiledevice. The user, for example, can input data to set one or moretemperature thresholds used by the controller 130 to determine actionsbased on system 100 conditions.

As described previously, controller 130 can be configured to receiveinputs from the temperature sensors 116, the humidity sensors 117, therefrigerant temperature sensor 128, and/or the pressure sensor 129 anddetermine appropriate actions based on the received inputs. For example,the controller 130 can be configured to receive temperature data fromthe temperature sensor 116A and/or temperature sensor 116B and, based atleast in part on the received temperature data, output a control signalto EEV1 and/or EEV2 to cause EEV1 and/or EEV2 to modulate between anopen or a closed position. As an example, if the controller determines,based at least in part on the temperature data received from temperaturesensor 116A and/or temperature sensor 116B, that the air conditioningsystem 100 should operate in a reheat mode, the controller 130 canoutput a control signal to EEV1 to either close completely or closepartially and another control signal to EEV2 to either open completelyor open partially. In this way, refrigerant flowing through thecondenser coil 102 can either be slowed or entirely cease flowingthrough the condenser coil 102 and begin flowing through the reheat coil120. As will be appreciated, by circulating the refrigerant through thereheat coil 120, the reheat coil can begin to release heat to theambient air and cause the air downstream of the evaporator coil 126 toraise in temperature. When the controller 130 determines that EEV1should be completely closed to cause refrigerant to cease flowingthrough the condenser coil 102, the controller 130 can also output acontrol signal to the condenser coil fan 110 to turn off or otherwisecease moving air across the condenser coil 102.

The controller 130 can be further configured to continue to monitor thetemperature data received from temperature sensor 116A and/ortemperature sensor 116B and determine, based at least in part on thetemperature data, that a position of EEV1 and/or EEV2 should bemodulated (e.g., actuated to a more closed position or more openposition) to ensure the air supplied to the building (e.g., as detectedby the temperature sensor 116A) is within an acceptable temperaturerange of the air returning from the building (e.g., as detected by thetemperature sensor 116B). For example, if the controller 130 determinesthat the temperature of the air supplied to the building should beraised (e.g., as indicated by the temperature data from the temperaturesensor 116A indicating that the air temperature downstream of the reheatcoil 120 is less than a threshold air temperature), the controller 130can output a control signal to open EEV2 to a more opened position. Thecontroller 130 can also output a control signal to close EEV1 to a moreclosed position. By modulating EEV2 to a more opened position and EEV1to a more closed position, the controller 130 can cause more refrigerantto flow through the reheat coil 120 and consequently add more heat tothe air supplied to the building Similarly, if the controller 130determines that the temperature of the air supplied to the buildingshould be lowered (e.g., as indicated by the temperature data from thetemperature sensor 116A indicating that the air temperature downstreamof the reheat coil 120 is greater than a threshold air temperature), thecontroller 130 can output a control signal to close EEV2 to a moreclosed position. The controller 130 can also output a control signal toopen EEV1 to a more opened position. By modulating EEV2 to a more closedposition and EEV1 to a more opened position, the controller 130 cancause less refrigerant to flow through the reheat coil 120 andconsequently lessen the amount of heat added the air supplied to thebuilding. By controlling EEV1 and/or EEV2 based on the temperature datafrom temperature sensor 116A and/or 116B, the controller 130 can beconfigured to ensure that the temperature of the air supplied to thebuilding remains within a comfortable temperature range (i.e., within apredetermined or user-inputted temperature range) but also that theevaporator coil 126 can be at a temperature where moisture in the airwill condense on the evaporator coil 126, reducing the humidity of theair in the building. As will be appreciated, the amount of reheatrequired by the system 100 can vary depending on the particularconditions. For example, if the evaporator coil 126 must operate at alow temperature to remove humidity from the building, greater reheat maybe required to raise the temperature of the air to within an acceptabletemperature range. Conversely, if the evaporator coil 126 is notrequired to operate a low temperature to remove humidity from thebuilding, only a small amount of reheat may be required. Accordingly,the controller can be configured to modulate EEV1 and/or EEV2 to ensurethe proper amount of reheat is provided by the system 100. Furthermore,as will be appreciated by one of skill in the art, closing or opening ofEEV2 can control the operating pressure and/or operating temperature ofthe reheat coil 120.

The controller 130 can be further configured to control EEV1 and/or EEV2to modulate a valve position of EEV1 and/or EEV2 to maintain a superheatof the refrigerant in the system 100. The controller 130 can receiverefrigerant temperature data from the refrigerant temperature sensor 128and/or refrigerant pressure data from pressure sensor 129 and determine,based at least in part on the refrigerant temperature data, that a valveposition of EEV1 and/or EEV2 should be modulated. For example, if thecontroller 130 determines that the superheat is outside of an acceptablesuperheat temperature range (e.g., above or below the superheattemperature range) or outside of an acceptable super heat pressure range(e.g., above or below the superheat pressure range), the controller 130can determine that a valve position of EEV1 and/or EEV2 should bemodulated.

When the controller 130 determines that EEV1 and/or EEV2 should bemodulated to control a superheat of the system 100, the controller 130can output a control signal to one EEV (e.g., either EEV1 and/or EEV2)to open to a fixed position and output another control signal tomodulate the other EEV (e.g., the other of either EEV1 and/or EEV2) tocontrol the superheat of the system 100. For example, if the controller130 determines that the system 100 should operate in a reheat mode andthat a relatively large amount of reheat is required (e.g., greater than60% reheat is required), the controller 130 can output a control signalto close or partially close EEV1 and open or partially open EEV2 tocause refrigerant to flow through the reheat coil 120. The controller130 can then receive temperature data from the refrigerant temperaturesensor 128 and/or refrigerant pressure data from pressure sensor 129 todetermine whether a superheat of the refrigerant in the system 100 iswithin an acceptable temperature and/or an acceptable pressure range. Ifthe superheat of the refrigerant is outside of the acceptabletemperature range and/or the acceptable pressure range, the controller130 can output a control signal to open or close EEV2 an appropriateamount to ensure the superheat is maintained within the acceptabletemperature range and/or the acceptable pressure range. On the otherhand, if the controller 130 determines that the system 100 shouldoperate in a reheat mode and that a relatively small amount of reheat isrequired (e.g., less than 60% reheat is required), the controller 130can output a control signal to partially close EEV2 and open orpartially open EEV1. The controller 130 can receive temperature datafrom the refrigerant temperature sensor 128 and/or refrigerant pressuredata from pressure sensor 129 to determine whether a super heat of therefrigerant in the system 100 is within an acceptable temperature rangeand/or the acceptable pressure range. If the superheat of therefrigerant is outside of the acceptable temperature range and/or theacceptable pressure range, the controller 130 can output a controlsignal to open or close EEV1 an appropriate amount to ensure thesuperheat is maintained within the acceptable temperature range and/orthe acceptable pressure range. In this way, both EEV1 and/or EEV2 can beused to control the reheat and the superheat of the system 100.

Alternatively or in addition, EEV2 can remain in a current openedposition, and the condenser coil fan 110 can be controlled to maintainan appropriate amount of reheat for the system 100. For example, thecontroller 130 can determine that additional heat should be rejected atthe condenser coil 102 and that the condenser coil fan 110 should beturned on for the condenser coil 102 to begin releasing further heat tothe ambient air (e.g., outdoor air). As will be appreciated, byreleasing further heat with the condenser coil 102, the amount of heatthat will be rejected by the reheat coil 120 to the indoor air will belimited because the amount of heat available from the refrigerant to thereheat coil 120 is also limited. In systems where the speed of thecondenser coil fan 110 can be modulated, the controller can output acontrol signal to modulate a speed of the condenser coil fan 110 toensure the reheat mode of the system 100 maintains the temperature ofthe air supplied to the building within an acceptable temperature range.

The controller 130 can also be configured to control a position of EEV1and/or EEV2 based on humidity data received from humidity sensor 117Aand/or humidity sensor 117B. For example, the controller 130 can beconfigured to receive humidity data from the humidity sensor 117A and/orhumidity sensor 117B and, based at least in part on the receivedhumidity data, output a control signal to EEV1 and/or EEV2 to cause EEV1and/or EEV2 to modulate between an open or a closed position. As anexample, if the controller 130 determines, based at least in part on thehumidity data received from humidity sensor 117A and/or 117B, that airconditioning system 100 should operate in a reheat mode, the controller130 can output a control signal to EEV1 to either close completely orclose partially and another control signal to EEV2 to either opencompletely or open partially. In this way, refrigerant flowing throughthe condenser coil 102 can either be slowed or entirely cease flowingthrough the condenser coil 102 and begin flowing through the reheat coil120. As will be appreciated, by circulating the refrigerant through thereheat coil 120, the reheat coil can begin to release heat to theambient air and cause the air downstream of the evaporator coil 126 toraise in temperature.

The controller 130 can be further configured to continue to monitor thehumidity data received from humidity sensor 117A and/or humidity sensor117B and determine, based at least in part on the humidity data, that aposition of EEV1 and/or EEV2 should be modulated to ensure the airsupplied to the building (e.g., as detected by humidity sensor 117A) hasless moisture content than the air returning to the air conditioningsystem 100 from the building (e.g., as detected by humidity sensor117B). As will be appreciated, the amount of reheat required by thesystem 100 can vary depending on the particular conditions. For example,if relative humidity in the building (e.g., as detected by humiditysensor 117A) is high, the evaporator coil 126 must operate at a lowtemperature to remove humidity from the building and greater reheat maybe required to raise the temperature of the air to within an acceptabletemperature range. Conversely, if the evaporator coil 126 is notrequired to operate at a low temperature to remove humidity from thebuilding, only a small amount of reheat may be required. Accordingly,the controller can be configured to modulate EEV1 and/or EEV2 to ensurethe proper amount of reheat is provided by the system 100 based on datareceived from humidity sensor 117A and/or humidity sensor 117B.

FIG. 2 is a flowchart illustrating an example method 200 of controllinga reheat cycle of an air conditioning system (e.g., air conditioningsystem 100), in accordance with the disclosed technology, and the method200 can cause the air conditioning system to transition from a fullcooling mode to a full reheating mode. The method 200 can includereceiving 202 temperature data (e.g., from an air temperature sensor)indicative of an air temperature in the air conditioning system anddetermining 204 that the air conditioning system should operate in areheat mode based at least in part on the air temperature being lessthan a threshold air temperature (e.g., less than approximately 60° F.).As mentioned previously, the temperature data can correspond to an airtemperature upstream of an evaporator coil and/or downstream of a reheatcoil. The method 200 can further include, in response to determiningthat the air conditioning system should operate in reheat mode,outputting 206 a control signal to a first electronic expansion valve toclose the first electronic expansion valve to prevent a refrigerant inthe air conditioning system from flowing through an outdoor condensercoil and outputting 208 a control signal to a second electronicexpansion valve to open the second electronic expansion valve to permitthe refrigerant to flow through a reheat coil. Alternatively oradditionally, the method 200 can include outputting 210 a control signalto the outdoor condenser coil fan to turn off.

FIG. 3 is a flowchart illustrating an example method 300 of controllinga reheat cycle of an air conditioning system (e.g., air conditioningsystem 100), in accordance with the disclosed technology, and the method300 can cause the air conditioning system to transition from the fullreheat mode to the full cooling mode. The method 300 can includereceiving 302 temperature data (e.g., from an air temperature sensor)indicative of an air temperature in the air conditioning system anddetermining 304 that the air conditioning system should operate in acooling mode based at least on the air temperature being greater than orequal to a threshold air temperature. The method 300 can further includeoutputting 306 a control signal to the first electronic expansion valveto open the first electronic expansion valve to permit a refrigerant inthe air conditioning system to flow through the outdoor condenser coiland outputting 308 a control signal to the second electronic expansionvalve to close the second electronic expansion valve to prevent therefrigerant from flowing through the reheat coil. Alternatively or inaddition, the method 300 can include outputting 310 a control signal tothe outdoor condenser coil fan to turn on.

FIG. 4 is a flowchart illustrating an example method 400 of controllinga reheat cycle of an air conditioning system (e.g., air conditioningsystem 100), in accordance with the disclosed technology. The method 400can include receiving 402 air temperature data (e.g., from an airtemperature sensor) indicative of an air temperature in the airconditioning system and receiving 404 refrigerant temperature data(e.g., from a fluid temperature sensor) indicative of a temperature ofrefrigerant in the air conditioning system. The method 400 can furtherinclude determining 406 that the air conditioning system should operatein a modulating reheat mode based at least on the air temperature beingless than a threshold air temperature and the refrigerant temperaturebeing less than a threshold refrigerant temperature. As will beappreciated, the threshold air temperature can be a user-inputtedtemperature and/or correspond to a predetermined temperature below whichan occupant of a building is likely to be uncomfortable. In this way,the method 400 can be used to ensure air supplied to the buildingremains within a comfortable temperature range for the occupants. Themethod 400 can include outputting 408 a control signal to the firstelectronic expansion valve to modulate the first electronic expansionvalve to control a flow of the refrigerant through the outdoor condensercoil. The method 400 can further include outputting 410 a control signalto the second electronic expansion valve to modulate the secondelectronic expansion valve to control a flow of the refrigerant throughthe reheat coil.

As will be appreciated, by controlling the flow of the refrigerantthrough the condenser coil and the reheat coil, the method 400 cancontrol the reheat of air being delivered to a building to ensure thetemperature of the air remains at a comfortable level. For example, inresponse to determining that the temperature of the air supplied to thebuilding should be raised (e.g., as indicated by the temperature datafrom the temperature sensor indicating that the air temperaturedownstream of the reheat coil is less than a threshold air temperature),the method 400 can include outputting a control signal to modulate thesecond electronic expansion valve to a more opened position.Additionally, the method 400 can include outputting a control signal tomodulate the first electronic expansion valve to a more closed position.By modulating the second electronic expansion valve to a more openedposition and first electronic expansion valve to a more closed position,the method 400 can cause more refrigerant to flow through the reheatcoil and consequently add more heat to the air supplied to the building.Similarly, the method 400 can include determining that the temperatureof the air supplied to the building should be lowered (e.g., asindicated by the temperature data from the temperature sensor indicatingthat the air temperature downstream of the reheat coil is greater than athreshold air temperature), the method 400 can include outputting acontrol signal to modulate the second electronic expansion valve to amore closed position. The method 400 can also include outputting acontrol signal to modulate the first electronic expansion valve to amore opened position. By modulating the second electronic expansionvalve to a more closed position and the first electronic expansion valveto a more opened position, the method 400 can cause less refrigerant toflow through the reheat coil and consequently lessen the amount of heatadded the air supplied to the building.

FIG. 5 is a flowchart illustrating an example method 500 of controllinga reheat cycle of an air conditioning system (e.g., air conditioningsystem 100), in accordance with the disclosed technology. The method 500can include receiving 502 air temperature data (e.g., from an airtemperature sensor) indicative of an air temperature in the airconditioning system and receiving 504 refrigerant temperature data(e.g., from a fluid temperature sensor) indicative of a refrigeranttemperature of refrigerant in the air conditioning system. The method500 can include determining 506 that the first electronic expansionvalve should be opened a predetermined amount (e.g., 10% capacity, 25%capacity, 50% capacity, 75% capacity, or any capacity betweenfully-opened and fully-closed) based on at least the air temperaturedata indicating that the air temperature is less than a first thresholdair temperature and less than a second threshold air temperature. Thefirst threshold air temperature can be greater than the second thresholdair temperature. As an example, the first threshold air temperature canbe a threshold temperature where a controller can determine that reheatis necessary to supply air to the building having a comfortable airtemperature. On the other hand, the second threshold air temperature canbe a threshold temperature where a controller can determine that themajority of refrigerant should flow through the reheat coil rather thanthrough the condenser coil to provide additional reheat to the airsupplied to the building. In this way, the controller can determine,based on the threshold temperatures, an appropriate amount of reheatthat is required for the system.

The method 500 can further include determining 508 that the secondelectronic expansion valve should be modulated based on at least therefrigerant temperature. The method 500 can include outputting 510 acontrol signal to the first electronic expansion valve to open the firstelectronic expansion valve a predetermined amount (e.g., 10% capacity,25% capacity, 50% capacity, 75% capacity, or any capacity betweenfully-opened and fully-closed) and outputting 512 a control signal tomodulate the second electronic expansion valve. The second electronicexpansion valve can be modulated to maintain the refrigerant temperaturebased on the threshold refrigerant temperature. For example, if therefrigerant temperature is greater than an acceptable thresholdrefrigerant temperature, the second electronic expansion valve can bemodulated to a more opened position to allow more refrigerant from thereheat coil to pass through the evaporator coil to maintain a suitablesuperheat of the refrigerant at the evaporator coil. Alternatively, ifthe refrigerant temperature is less than an acceptable thresholdrefrigerant temperature, the second electronic expansion valve can bemodulated to a more closed position to allow less refrigerant from thereheat coil to pass through the evaporator coil to maintain a suitablesuperheat of the refrigerant at the evaporator coil. As will beappreciated, the refrigerant temperature can be indicative of thesuperheat of the refrigerant in the air conditioning system and thesecond electronic valve can be modulated to ensure the superheat ismaintained within an acceptable range.

The method 500 can also include determining 516 that the outdoorcondenser coil fan should be operated based on the refrigeranttemperature data indicating that the temperature of the refrigerant isless than the threshold refrigerant temperature and outputting 516 acontrol signal to operate the outdoor condenser coil fan. Operating theoutdoor condenser coil fan can include simply turning on the outdoorcondenser coil fan or modulating a speed of the outdoor condenser coilfan.

FIG. 6 is a flowchart illustrating an example method 600 of controllinga reheat cycle of an air conditioning system (e.g., air conditioningsystem 100), in accordance with the disclosed technology. The method 600can include receiving 602 temperature data (e.g., from an airtemperature sensor) indicative of an air temperature in the airconditioning system and receiving 604 temperature data (e.g., from arefrigerant temperature sensor) indicative of a refrigerant temperatureof refrigerant in the air conditioning system. The method 600 caninclude receiving 606 pressure data indicative of a pressure ofrefrigerant in the air conditioning system (e.g., from a pressuresensor). The method 600 can further include determining 608 that thesecond electronic expansion valve should be opened a predeterminedamount (e.g., 10% capacity, 25% capacity, 50% capacity, 75% capacity, orany capacity between fully-opened and fully-closed) based on the airtemperature data indicating that the air temperature is less than thethreshold air temperature and greater than the second threshold airtemperature, the threshold air temperature being greater than the secondthreshold air temperature. Similar to the method 500, in this example,the first threshold air temperature can be a threshold temperature wherea controller can determine that reheat is necessary to supply air havinga comfortable air temperature to the building. On the other hand, thesecond threshold air temperature can be a threshold temperature where acontroller can determine that the majority of refrigerant should flowthrough the reheat coil rather than through the condenser coil toprovide additional reheat to the air supplied to the building. In thisway, the controller can determine, based on the threshold temperatures,an appropriate amount of reheat that is required for the system.Furthermore, the first and second threshold temperatures can both be auser inputted value.

The method 600 can further include determining 610 that the firstelectronic expansion valve should be modulated based on at least therefrigerant temperature and/or the refrigerant pressure. The method 600can include outputting 612 a control signal to the second electronicexpansion valve to open the second electronic expansion valve apredetermined amount (e.g., 10% capacity, 25% capacity, 50% capacity,75% capacity, or any capacity between fully-opened and fully-closed) andoutputting 614 a control signal to modulate the first electronicexpansion valve. The first electronic expansion valve can be modulatedto maintain the refrigerant temperature and/or pressure based on thethreshold refrigerant temperature and/or the threshold refrigerantpressure. For example, while monitoring the refrigerant pressure, if therefrigerant temperature is greater than an acceptable thresholdrefrigerant temperature, the first electronic expansion valve can bemodulated to a more opened position to allow more refrigerant from thecondenser to pass through the evaporator coil to maintain a suitablesuperheat of the refrigerant at the evaporator coil. Alternatively, ifthe refrigerant temperature is less than an acceptable thresholdrefrigerant temperature, the first electronic expansion valve can bemodulated to a more closed position to allow less refrigerant from thecondenser to pass through the evaporator coil to maintain a suitablesuperheat of the refrigerant at the evaporator coil. As will beappreciated, the refrigerant temperature can be indicative of thesuperheat of the refrigerant in the air conditioning system and thefirst electronic valve can be modulated to ensure the superheat ismaintained within an acceptable range.

The method 600 can also include determining 616 that the outdoorcondenser coil fan should be operated based at least on the refrigeranttemperature data indicating that the temperature of the refrigerant isless than the threshold refrigerant temperature and outputting 618 acontrol signal to operate the outdoor condenser coil fan Similar to themethod 500, operating the outdoor condenser coil fan in this example caninclude simply turning on the outdoor condenser coil fan or modulating aspeed of the outdoor condenser coil fan.

As will be appreciated, the methods 200, 300, 400, 500, and 600 justdescribed can be varied in accordance with the various elements andexamples described herein. That is, methods in accordance with thedisclosed technology can include all or some of the steps describedabove and/or can include additional steps not expressly disclosed above.Further, methods in accordance with the disclosed technology can includesome, but not all, of a particular step described above. Further still,various methods described herein can be combined in full or in part.That is, methods in accordance with the disclosed technology can includeat least some elements or steps of a first method (e.g., method 200,etc.) and at least some elements or steps of a second method (e.g.,method 300, etc.). Moreover, the methods described herein, or portionsthereof, can be embodied in computer instructions (e.g., in anon-transitory, computer readable medium).

While the present disclosure has been described in connection with aplurality of exemplary aspects, as illustrated in the various figuresand discussed above, it is understood that other similar aspects can beused, or modifications and additions can be made to the describedaspects for performing the same function of the present disclosurewithout deviating therefrom. For example, in various aspects of thedisclosure, methods and compositions were described according to aspectsof the presently disclosed subject matter. But other equivalent methodsor compositions to these described aspects are also contemplated by theteachings herein. Therefore, the present disclosure should not belimited to any single aspect, but rather construed in breadth and scopein accordance with the appended claims.

That which is claimed is:
 1. A method of controlling an air conditioningsystem, the method comprising: determining, using a first sensor, afirst refrigerant temperature value of a refrigerant in the airconditioning system; determining that the first refrigerant temperaturevalue is less than a threshold refrigerant temperature value; causing afirst electronic expansion valve to modulate a flow of the refrigerantthrough an outdoor condenser coil of the air conditioning system; andcausing a second electronic expansion valve to modulate a flow of therefrigerant through a reheat coil of the air conditioning system.
 2. Themethod of claim 1, further comprising: determining, using a secondsensor, a first air temperature value of air in the air conditioningsystem; and prior to causing the first electronic expansion valve tomodulate the flow of the refrigerant, determining that the first airtemperature value is less than a threshold air temperature value.
 3. Themethod of claim 2, wherein the first air temperature value is a returnair temperature value of air that is returned to the air conditioningsystem.
 4. The method of claim 2, further comprising: determining a userinput corresponding to the threshold air temperature value.
 5. Themethod of claim 2, wherein the second sensor is disposed downstream ofthe reheat coil.
 6. The method of claim 1, further comprising:determining that a temperature of air discharged by the air conditioningsystem is to be increased; causing the first electronic expansion valveto move to a fully closed position; and causing the second electronicexpansion valve to move to a fully opened position, such that therefrigerant flows through the reheat coil.
 7. The method of claim 6,further comprising: causing an outdoor condenser coil fan to activate.8. The method of claim 7, wherein causing the outdoor condenser coil fanto activate comprises: determining that a speed of the outdoor condensercoil fan should be modulated based at least in part on a differencebetween the first refrigerant temperature value and the thresholdrefrigerant temperature value; and causing the outdoor condenser coilfan to modulate the speed.
 9. The method of claim 1, further comprising:determining that a temperature of air discharged by the air conditioningsystem is to be reduced; causing the first electronic expansion valve tomove to a fully open position, such that the refrigerant flows throughthe outdoor condenser coil; and causing the second electronic expansionvalve to move to a fully closed position.
 10. The method of claim 1,wherein the first refrigerant temperature value is indicative ofsuperheated refrigerant flowing through an evaporator.
 11. The method ofclaim 1, further comprising: causing an outdoor condenser coil fan todeactivate.
 12. The method of claim 1, wherein causing the firstelectronic expansion valve to modulate the flow of the refrigerantcomprises: causing, based at least in part on the first refrigeranttemperature value being less than the threshold refrigerant temperaturevalue, the first electronic expansion valve to modulate the flow of therefrigerant through the outdoor condenser coil of the air conditioningsystem.
 13. The method of claim 1, further comprising: determining,using a second sensor, humidity data indicative of a humidity level ofair in the air conditioning system; and determining that the airconditioning system should operate in a reheat mode based at least inpart on the humidity level being greater than a threshold humiditylevel.
 14. A method of controlling an air conditioning system, themethod comprising: determining, using a first sensor, a first airtemperature value of air in the air conditioning system; determiningthat the first air temperature value is less than a threshold airtemperature value; causing a first electronic expansion valve tomodulate a flow of the refrigerant through an outdoor condenser coil ofthe air conditioning system; and causing a second electronic expansionvalve to modulate a flow of the refrigerant through a reheat coil of theair conditioning system.
 15. The method of claim 14, further comprising:determining, using a second sensor, a first refrigerant temperaturevalue of a refrigerant in the air conditioning system; and prior tocausing the first electronic expansion valve to modulate the flow of therefrigerant, determining that the first refrigerant temperature value isless than a threshold refrigerant temperature value.
 16. The method ofclaim 14, wherein the first air temperature value is a return airtemperature value of air that is returned to the air conditioningsystem.
 17. The method of claim 14, further comprising: determining auser input corresponding to the threshold air temperature value.
 18. Themethod of claim 14, further comprising: determining that a temperatureof air discharged by the air conditioning system is to be increased;causing the first electronic expansion valve to move to a fully closedposition; and causing the second electronic expansion valve to move to afully opened position, such that the refrigerant flows through thereheat coil.
 19. The method of claim 14, further comprising: determiningthat a speed of an outdoor condenser coil fan should be modulated basedat least in part on a difference between the first refrigeranttemperature value and the threshold refrigerant temperature value; andcausing the outdoor condenser coil fan to modulate the speed.
 20. Themethod of claim 14, further comprising: determining that a temperatureof air discharged by the air conditioning system is to be reduced;causing the first electronic expansion valve to move to a fully openposition, such that the refrigerant flows through the outdoor condensercoil; and causing the second electronic expansion valve to move to afully closed position.